Golfers are presented with the same challenge on every golf hole. This challenge is to putt the golf ball into the hole in as few strokes as possible. To do this requires that the ball be stroked to successfully traverse an expanse of grassy terrain that is not flat or level. Determining just how to compensate for the terrain irregularities of a golf green requires an accurate assessment of the magnitude of these irregularities, particularly the slope of the green. This enables the golfer to measure the slope of a golf green to aid in determining the proper "line" that the putt must take.
Devices have been developed to aid golfers by indicating the deviation of the green slope from level. One such device is presented in U.S. Pat. No. 4,082,286, in which a spirit level and slope measurement chart are incorporated into the head of a putter. This device is of limited utility since it is linear and will only display the slope of the green transverse to the line of the putt, indicating only a break to the left or right. It will not display the absolute slope of the green, which is useful in determining whether the putt is uphill or downhill. Another is shown in U.S. Pat. No. 5,669,832 in which a tripod incorporates a spirit level that is placed over a ball. Another is shown in U.S. Pat. No. 5,476,258 which discloses a ball marker having a so-called "bulls-eye level" comprising a flat chamber filled with oil of specific viscosity and a steel ball; slope is determined by the speed at which the steel ball traverses the oil in the chamber.
All of these prior art devices are either bulky, unduly complex, expensive or provide only incomplete information. Thus there is a need for golf green slope indicator which is simple in construction, inexpensive and provides information on the absolute slope of the green.